JPS63225301A - Production of agricultural chemical pharmaceutical - Google Patents

Abstract

PURPOSE:To obtain an agricultural pharmaceutical, by the presence of at least one agricultural chemical ingredient or adding agricultural chemical ingredients after forming a gel, impregnating the gel with the ingredients and drying the resultant gel in subjecting a specific alkyl silicate to hydrolysis and polycondensation reaction. CONSTITUTION:At least one alkyl silicate expressed by formula I [R1-R4 are H or formula II (X is 1-5; y is 0-10) and all R1-R4 are not H; n is 0-20] (e.g. a compound expressed by formula III) is subjected to hydrolysis and polycondensation reaction. In the process, the above-mentioned reaction is carried out in the presence of an agricultural chemical ingredient (especially preferably herbicide or insecticide) or a gel is formed by the afore-mentioned reaction, then impregnated with the agricultural chemical ingredients and dried to afford an agricultural chemical pharmaceutical. Thereby the pharmaceutical in the form of the agricultural ingredients sufficiently contained even to the interior of powder is obtained and the efficacy of an agricultural chemical having a short life and low residual effect can be sustained for a long period. The pharmaceutical has water resistance without causing phytotoxicity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing an agrochemical formulation carrying a medicinal ingredient of an agrochemical.

[Conventional technology]

Pesticides are applied to soil, plants, etc., and it is preferable that the applied pesticide is stable and has excellent long-lasting effects. However, in reality, it is difficult to achieve a sustained effect, and the current situation is to spray more pesticides than necessary at one time or to increase the number of sprays. However, when spraying in large quantities, there are serious problems with the effects on objects other than the target, such as chemical damage and residue, and it is also extremely uneconomical.On the other hand, when the number of spraying groups is increased, spraying takes time and effort. Considering the current situation where labor saving is desired, this is not desirable. moreover,
According to these methods, pesticides run off in the rain and enter rivers, causing damage to fish and shellfish.In addition, in the case of herbicides, the pesticides spread deep into the soil due to rain, reaching the roots of crops, and damaging the crops. There are problems such as chemical damage to the skin.

One way to deal with this is to use pesticides that are stable and long-lived, but on the other hand, such pesticides decompose slowly, remain for a long time, and may be incorporated into the food chain. Use is severely restricted.

Therefore, various methods have been developed to maintain the efficacy of pesticides with short lifespans and low residual effects over long periods of time. For example, there is a method of microencapsulating pesticides using polymeric microcapsules, but this method has the problem that the polymer has poor biodegradability and is likely to have a negative impact on the environment. There is a method in which pesticides are adsorbed onto inorganic substances such as silica, but this method is not water resistant and has the problem that the pesticides are released all at once by rain or large amounts of water.

Furthermore, a method of using powdered hydrated silicic acid in which the volume occupied by pores of 150 Å or less in the pore size distribution is 0.5 to 2 CC/g as a carrier for agricultural chemicals, and mixing the agricultural chemicals with this 55-85502), a method using a carrier having a specific ratio of two specific types of pore radii (Japanese Patent Application Laid-open No. 56-86102), and a method in which the heat of immersion in water is 1Qcaβ/g or less A method using finely powdered hydrated silicic acid (Japanese Unexamined Patent Publication No. 148702/1983) has been proposed. However, in these methods, after preparing a carrier, pesticide components are added to the carrier and adsorbed onto the carrier, and the sustainability of the pesticide is still insufficient.

[Problem that the invention seeks to solve]

Therefore, an object of the present invention is to provide a method for producing an agrochemical formulation that has high persistence, water resistance, and does not cause chemical damage when applied to soil, plants, etc.

[Means for solving problems]

The present invention is characterized in that at least one pesticide component is present when a specific alkyl silicate is subjected to hydrolysis and polycondensation reaction to form a gel, or after the gel is formed, the pesticide component is added and impregnated into the gel. When the gel is dried, a form in which the pesticide ingredients are sufficiently contained inside the powder is obtained.
This was done based on the knowledge that the above-mentioned problems could be solved very effectively since the agricultural chemical components would be released slowly from inside the powder.

That is, the present invention is based on the general formula [■]: (wherein, R1-R4 are hydrogen or CXH2X-+ (OCJ4)y (wherein, X is 1 to 5,
y represents an integer of 0 to 10. ) is a group represented by
Not all of R1-R4 are hydrogen. n is 0~
It is an integer of 20. ) A hydrolysis or polycondensation reaction of at least one alkyl silicate represented by () is performed in the presence of a pesticide component to form a gel, or after a gel is formed by the reaction, the gel is impregnated with a pesticide component. Provided is a method for producing an agrochemical formulation, which is characterized in that the agrochemical formulation is then dried.

In the present invention, an alkyl silicate represented by the above general formula CI] is used as a raw material. Among these, in the formula, R1-R
4 is CH3, C2H8, n-C3H7,"l
150-C3Ht, n-C4tls, -C2HJ
CL is preferred, particularly preferably R1-R4 are the same group. Further, X is preferably 1 to 3, y is preferably 0 to 2, and n is preferably 0 to 10. Among these, in the present invention, those where n=o are particularly preferred, but condensates where n is 1 to 10 are also preferred. Specific examples of the silicate ester represented by the general formula [I] include methyl silicate, ethyl silicate,
n-propyl silicate, isopropinope silicate n-
Putinopesiliic acid 2-methoxyethinope These 2 to 10
Examples include quantities. Among these, ethyl silicate St
(OC2H5) s is ethyl silicate 28, an average 5 mol condensate of ethyl silicate: is easily available as ethyl silicate 40 from Colcourt.

The above-mentioned silicate ester or condensate thereof is hydrolyzed in water or a water/alcohol solvent, or under an acid or alkali catalyst, and the homogeneous solution is allowed to stand, or left to gel after being made into a pH l. At this time, in order to obtain a strong gel, it is preferable to perform hydrolysis under an acid catalyst. In the above reaction, a polycondensation reaction occurs between the silicate esters simultaneously with the hydrolysis, and 5i-0-3i bonds are formed in three dimensions to form a stable gel.

The present invention is characterized in that the hydrolysis and polycondensation reactions for forming the gel are carried out in the presence of an agricultural chemical component, or the gel is impregnated with the agricultural chemical component after gel formation. The agricultural chemical component that can be used here may be any component that is included in agricultural chemicals, as long as it is soluble in water or alcohol, or emulsifiable or dispersible with a surfactant. It is also possible to use agricultural chemicals that have been formulated into wettable powders, emulsions, liquids, aqueous solutions, and the like. Specifically, triazine series (simazine, atrazine, etc.), dinitroaniline series (triflualine, etc.), phenoxyacetic acid series (2,4-D, 2,4-PA, etc.), amide series (
butachlor, etc.), diphenyl ether-based (bifenox, chromethoxynil, etc.), urea-based (diuron, methyldaimeron, DCMU, etc.), aryloxypropionic acid-based (fluazifob, etc.), carbamate-based (IPC, etc.) herbicides, organophosphorus herbicides (ECP, etc.) agent, EPN agent, ESP agent, M E
P agents, etc.), pyrethroids, chlorine (chlordane,
Examples include one type of insecticide or a mixture of two or more types of insecticides such as Kelsen's agent.

These pesticide ingredients can be used in any amount, but
It is usually 0.1 to 30% by weight (hereinafter abbreviated as %), preferably 1 to 20%, based on the silicate ester, and if the agricultural chemical component is soluble in water or alcohol, it may be added as is or 1% by weight. It is preferable to add the compound by dissolving it in water or alcohol to a concentration of ~50%, or if it does not dissolve, it is preferable to emulsify or disperse it in water using a surfactant or the like and add it. still,
Many pesticides deteriorate under acidic conditions, so the pH should be around neutral.
It is preferable to add it after adjustment.

In the present invention, when an agrochemical component is present during polycondensation of alkyl silicate, the agrochemical component becomes gelled in a state in which it is entangled with the three-dimensional Sl-〇-3i bonds. In addition, immediately after gelation, the Si -0-3i bonds are loose, and even if the gel in this state is impregnated with pesticide ingredients, the pesticide ingredients will penetrate deep into the gel, resulting in the same state as when the pesticide ingredients are added during the reaction. It becomes.

In preparing the above-mentioned gel, hydrolysis is faster at lower pH, and gelation of the hydrolyzed liquid is faster at higher pH. Therefore, for efficient gelation, it is preferable to hydrolyze at a low pH 1, for example, pH 0.5 to 3.0, and then adjust the pH to around neutrality, that is, pH 4.0 to 8.0.

At this time, to make the pH of the liquid acidic, it is best to use mineral acids such as hydrochloric acid, nitric acid, and sulfuric acid, and organic acids such as acetic acid, citric acid, and lactic acid. , aqueous ammonia, sodium hydroxide, potassium hydroxide, monoethanolamine, jetanolamine, triethanolamine, etc. are preferably used.

In addition, the amount of water in the reaction system should be the minimum amount necessary for hydrolysis, and it can be added until it is diluted and no longer forms a gel, but it is usually 0.5 to 95%, preferably 1 to 95%, in the reaction solution.
It is preferable to use it so that the content is 70%. Note that if the agricultural chemical component is hydrophilic, it is preferable to increase the amount of water.

In the present invention, since alcohol is generated by the hydrolysis of the silicate ester, there is no need to separately add alcohol, but alcohol makes the distribution of pesticide components in AnoC uniform and solubilizes the pesticide components. , preferably contained in the reaction solution in an amount of 0.1 to 95%. In addition, when the agricultural chemical component is alcohol-soluble, it is preferable that the amount of alcohol is large.

At this time, the alcohol to be added separately is preferably of the same type as the alcohol produced by hydrolysis of the silicate ester, but a different type of alcohol may be used.

In the present invention, after the above-mentioned gelation reaction is carried out at 0 to 80° C., the gel containing the agricultural chemical component is dried by a conventional method to produce a dry gel, which is pulverized to obtain a powder containing the agricultural chemical.

At this time, the gel is dried under normal pressure or reduced pressure at 0 to 100°C, preferably 15 to 60°C, until the gel weight does not change. During this drying process, the polycondensation reaction progresses further, and the gel gradually becomes harder while still trapping the pesticide components.

Next, the dried gel is ground, but the gel may be ground and then dried.

In the present invention, various components can be added as desired in the above manufacturing process. For example, metal alkoxides, such as
Polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, polyacrylamide, polyacrylic acid, polyacrylate esternope, polyvinyl acetate, guar gum, carrageenan, hydroxyethylcellulose, hydroxypropylcellulose, and inorganic powders for agricultural chemical carriers can be added. .

〔Effect of the invention〕

According to the present invention, a pesticide formulation that is resistant to rain and has a long-lasting effect can be obtained. Therefore, according to this, excessive diffusion of agricultural chemicals can be prevented and chemical damage can be prevented.

In addition, when a herbicide is selected as the agricultural chemical component, the herbicide of the present invention becomes a formulation that provides selectivity even if it is non-selective, and acts only on weeds on the soil surface, and its diffusion into the soil is small, so it is effective against crops. It has an excellent effect of not causing any harm to the people.

Therefore, it can be used as a wide range of agricultural chemicals by selecting herbicides, insecticides, fungicides, rodenticides, plant growth promoters, etc. as agricultural chemical components.

Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

Example 1 22.5 g of 28 mmol 1/12 hydrochloric acid water was added to 52.1 g (0.25 mol) of si(OC28s) and stirred to obtain a homogeneous solution after 1 hour. Add 1.25 g of Methyl Daimeron to this liquid.

When 5 g of DcMUl and 0.75 g of 2.4-PA were added and stirred, gelation occurred after 15 minutes. 4 times this gel
After drying at 5° C. for one week, it was crushed to obtain silica powder containing the herbicide.

In order to examine the water resistance and sustained release properties of this herbicidal preparation, 1.5 g of the preparation of the present invention was mixed with 2Qmj! The filtrate was collected and the washing was repeated again. Absorbent cotton was soaked with each filtrate, 20 crabgrass seeds were placed on top, and the germination rate was examined one week later.

For comparison, the same amount of herbicide was adsorbed onto wet silica.

Table 1 shows the number of times of water washing and the germination rate of crabgrass in the filtrate.

Table 1 [From Table 1, it can be seen that no germination of crabgrass was observed in the filtrate of the first washing with water in both the inventive product and the comparative product, indicating that the herbicide was released into the water in both cases. However, in the filtrate of the second washing with water, no germination was observed in the product of the present invention, whereas in the comparative example, 50% of the crabgrass germinated, indicating that the herbicidal effect was lost. This is thought to be because a large amount of the herbicide adsorbed on the silica of the comparative example was released into the water during the first water washing. On the other hand, the product of the present invention showed a herbicidal effect with a germination rate of 20% even after 5 washings, and was excellent in both sustained release and sustainability even under such harsh conditions.

Example 2 Ethyl silicate 40 28 mmo 1 in 37.5 g
22.5 g of 1/1 hydrochloric acid solution was added and stirred to obtain a homogeneous solution after 1 hour. After adjusting the pH of this liquid to 5 with 172N aqueous ammonia, 5 g of lasso emulsion was added and stirred. This solution was allowed to stand overnight at 45°C to form a gel. This gel was dried under reduced pressure and then ground to obtain silica powder containing the herbicide. Corn seeds were planted 3 cm below the ground surface, and the powder was spread on a circumference 5 cm away from the point where the seeds were planted.

Thereafter, the powder was sprinkled with water once each day for three days, and then the seeds of crabgrass were sown on the powder. In addition, as a comparison, the above operation was carried out using silica synthesized by a wet method to which the same amount of lasso emulsion was adsorbed.

In the case of the product of the present invention, crabgrass did not germinate, whereas corn germinated normally. On the other hand, in the case of the comparative example, crabgrass showed a germination rate of 30%, whereas corn did not germinate and suffered from chemical damage.

Claims (2)

[Claims] (1) General formula [I]: ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・[I
] (In the formula, R_1 to R_4 are hydrogen or C_xH_2_k_+_1(OC_2H_4)_y-(
However, x represents an integer of 1 to 5, and y represents an integer of 0 to 10. ), but not all of R_1 to R_4 are hydrogen. n is an integer from 0 to 20. ) A hydrolysis or polycondensation reaction of at least one alkyl silicate represented by the following formula is performed in the presence of a pesticide component to form a gel, or after a gel is formed by the reaction, the gel is impregnated with a pesticide component. A method for producing an agrochemical formulation, which comprises drying the formulation. (2) Claim No. (1) in which the agricultural chemical component is a herbicide
The method described in section.